This commit improves some FTP implementation details for better
compatibility with FTP clients:
* The PWD command now puts quotes around the directory name before
returning it. This fixes BBEdit’s FTP client, which performs a PWD after
each CWD and gets confused if the returned directory path is not
surrounded by quotes.
* The FEAT command is now allowed before logging in. This fixes the lftp
client, which send FEAT first and gets confused (tries to use TLS) if the
server responds with 332.
Header files that are considered internal to the py core and should not
normally be included directly are:
py/nlr.h - internal nlr configuration and declarations
py/bc0.h - contains bytecode macro definitions
py/runtime0.h - contains basic runtime enums
Instead, the top-level header files to include are one of:
py/obj.h - includes runtime0.h and defines everything to use the
mp_obj_t type
py/runtime.h - includes mpstate.h and hence nlr.h, obj.h, runtime0.h,
and defines everything to use the general runtime support functions
Additional, specific headers (eg py/objlist.h) can be included if needed.
This is to keep the top-level directory clean, to make it clear what is
core and what is a port, and to allow the repository to grow with new ports
in a sustainable way.
